Incandescent electric lamp



' 1,641,06 Aug. 30, 1927. F. CZECH INCANDESCENT ELECTRI C LAMP Filed June 17 1925 Patented Auig. 30, 192'37.

UNITED -STATES FRED CZECH, OF WICHITA FALLS, TEXA.

INCANDEscENr nnncrmc'mme.

Application led June 17, 1925/. Serial No. 37,781.-

This invention relates to improvements in electric lamps of the incandescent type and hasfor its principal object to 'provide a lamp -wherein a pair of independent filaments is provided, so that when one of the filaments should burn out or accidentally become broken, the other filament will be adapted to function so as to enable the electric'lamp to be further used until said last mentioned filament burns out or becomes broken.

Another important object of the invention is to providean incandescent lamp of the above mentioned character wherein the same has its base provided with a pair of independent positive contacts which 4are adapted to cooperate with the socket provided for the base of the'electric lamp, one of saidY contacts being rendered inoperative when the other contact is in use.

A still further object, is to provide an incandescent lamp of the above mentioned character which is simple in construction, inexpensive, strong and durable, and further well adapted to the purpose for which 5 it is designed.

Other objects and advantages of this invention will become apparent during the course of the following description taken in connection with the accompanying drawing.

In the'accompanying drawing forming a Vpart of this application and in which like numerals designate like parts throughout the same: v

Figure 1 is a side elevation of the incan- 35 descent lamp embodyingmy invention, and

Figure 2 is an enlargedfragmentary sectional view showing the relation of the lead in wires with respect to the shell which surrounds the base.y Y y R In the drawing, wherein for the purpose of illustration is shown the preferred embodiment of my invention, the'numeral 1` designates generally my improved incandescent lamp, the same comprising the base 2,

v the metallic shell 3 which encircles the saine,A

and is provided with a means for securing the lamp in theA well known type of socket.

Embedded in the base and extended upso wardly therefrom is the usual glass plug 4,

and the bulb which encl'osed the the filaments is indicated at' 5.

4 The positive terminal or contact 6 which is provided` at the bottom ofthe base 2 has I associated therewith the spring strip 7, the

purpose' of which will, hereinafter be more plug` and;

primary filament is connected to the' outerfree end of the diverging portion 1l of the lead in wire 12 which extends through the glass plug 4, and theside of the upper portion of the base 2 engages the negative contact 'or shell 3 as at 13. This lamp as above described is of the well knowp type 'pf a single filament lamp, and when the filament burns out or accidentally becomes broken,

the lamp is rendered useless and must necessarily be replaced with a. new one.

In order to overcome the above disadvantages.v I have provided an auxiliary filament in connection with the primary filament so that when the primary filament becomes` 'burnt out or broken, the lamp need not be thrown away but may be further used, thus saving considerable expense. The construction of the auxiliary filament and the supporting means therefor will be presently de- Extending upwardly from the main lead in wire 8 'at a point adjacent the juncture of the diverging portion 9 is the wire 14. An additional lead in wire 15 extends longitudinally through \the, glass plug 4, and the upper ends of the wires 14 and 15 are conl nected through the medium of the auxiliary filament 16. The lower end of the lead in wire `15 extends laterally through the plug 4, and is connected to the contact 17 which extends outwardly of the metallic-shell 3 adjacent the upper edge thereof and is insulated as at 18. t f' Under normal conditions, when the incandescent lamp is in its socket. the Contact' 17 does not engage the socket and the current will flow through the wires Sand 12, and the primary filaments 10, whereby the llamps will be properly illuminated.y When the primary filament ceases to function, it is only necessary to further screw the shell 3 of'the lamp into the socket provided therefor, so that the contact- 17 will engage the metallic portion of socket, and thus enable the current to flow through the wires 8 and 15, and through the auxiliary filament 1 6.

In this manner the auxiliary lilamentwill render the lamp luminous.

It will thus be seen from the foregomg description,- that a double filament incandescent lamp has been provided which will be very inexpensive in its manufacture, and furthermore at all times positive and eicient in carrying out the-purposes for which the same is designed. i

Thile I have shown the' preferred embodiment of my invention, it is to be understood that minor changes in the size, shape and arrangement of parts may be resorted to without departing from the spirit of )the invention and the scope of the appended claim.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent` 'iszf An incandescent lamp comprising a base, a metallic shell surrounding the same, aglass plug carried by the base, a bulb enclosing the same, agit-'erminal \at the bottom of the base, a` main lead in wire extending through the base and said plug and connected at its lower end to said terminal, a com.-

plementary lead in wire extending through the plug, a lower end thereof bemg in engagement with said metallic shell, a primary filament bridging the upper end of said wires, a contact carried by the base and extending throngh the shell at a oint adjacent the upper edge thereof, an being 1nsulated therefrom, an additional lead in wire connected at its lower end with said contact and extending upwardly throughthe plug, a branch wire extending upwardly from the main lead in wire, anA auxiliary l filament bridging the upper ed e of the branch Wire and the last mentione `lead in wire, and a spring strip carried by the base and being in engagement with theu terminal, the aforementioned contact being out of enga" ement with a. lamp receiving socket when t e primary filament is in use, said springstrip permitting the plug to be inserted in its socket so asto bring the contact into eng ement with the socket when the primary ainent is rendered inoperative.

In testimony whereof I aix my signature.'

FRED CZECH, 

